Method of installing a wellhead system



Feb. 10, 1970 w. w. DO LLISON METHOD OF INSTALLING A WELLHEAD SYSTEM 4 Sheets-Sheet 1 Original Filed Nov. 29, 1965 William W. Dollison fhz w @QWQQQQQ Fig.|

BY ATTO RNEYS Feb. 10, 1970 w, w, DOLUSON 3,494,421

METHOD OF INSTALLING A WELLHEAD SYSTEM Original Filed Nov. 29, 1965 4 Sheets-Sheet 2 s r 82 I05 2 so 9o 21! I J32 h4 5 Fig.7 70

24 24 (as I 72 704 63 i b I 65 I I l I I I I I l 1'22 Fig.8 INVENTOR William W. Dollison ATTORNEYS Feb. 10, 1970 w. w. DOLLISUN- 3,494,421

METHOD OF INSTALLING. A WELLHEAD SYSTEM Original Filed Nov. 29, 1965 4 Sheets-Sheet 5 Feb. 10, 1970 Original Filed Nov. 29, 1965 385 373 sea w. w. DQ LLISON 3,494,421

METHOD OF INSTALLING A WELLHEAD SYSTEM 4 Sheets-Sheet 4 CONT/P01.

STAT/0N 300/ 95 I *320 37s I 384 3sr a m 22 I' 32 i 23 i Fig.9

22 Fig. IO

1 mvsmox William W. Dollison ATTORNEYS United States Patent 3,494,421 METHOD OF INSTALLING A WELLHEAD SYSTEM William W. Dollison, Dallas, Tex., assignor to Otis Engineering Corporation, Dallas, Tex., a corporation of Delaware Original application Nov. 29, 1965, Ser. No. 510,189, now Patent No. 3,426,845, dated Feb. 11, 1969. Divided and this application June 4, 1968, Ser. No. 754,165

Int. Cl. E21b 23/00, 7/12 US. Cl. 166-315 6 Claims ABSTRACT OF THE DISCLOSURE This application is a division of application Ser. No. 510,189, filed Nov. 29, 1965, now Patent No. 3,426,845.

This invention relates to well tools and methods of installing such tools and more particularly to a wellhead installable through conduit means including pressure protection devices such as blowout preventers.

It is a particularly important object of this invention to provide a new and novel wellhead especially adapted to installation and operation at remote locations such as underwater.

It is another important object of this invention to provide a wellhead which may be inserted into operating position within a housing through a well conduit including devices such as blowout preventers supported above the housing.

It is another object of the invention to provide a wellhead or Christmas tree in the form of a cartridge which is lowered through a conductor pipe into operating position.

It is a further object of the invention to provide a wellhead which includes a plurality of valves operable by fluid pressure applied from a remotely located control station.

It is a still further object of the invention to provide a wellhead including at least one fluid actuated master valve for each tubing string connected into the head and at least one fluid actuated valve connected into the tubing-casing annulus of the well on which the head is installed.

It is still another object of the invention to provide a wellhead or Christmas tree cartridge encasing several fluid actuated valves without protruding handles and the like thereby permitting movement of the wellhead through conduits and equipment such as blowout preventers during installation and removal of the wellhead.

It is a still further object of the invention to provide an underwater wellhead which may be completely closed and sealed within an environment such as water and connected with flexible flow lines extending from the wellhead to a remotely situated control station and fluid handling facility.

It is still another object of the invention to provide an underwater wellhead having a substantially tubular-line body completely enclosing the fluid flow control components of the wellhead and having means for connection into flow lines only at opposite ends of the wellhead thereby minimizing exposure of the functioning elements 3,494,421 Patented Feb. 10, 1970 of the wellhead to water both during installation and operation of the wellhead.

It is a still further object of the invention to provide an underwater wellhead including fail-safe type, fluid operated, tubing and casing annulus valves.

It is a still further object of the invention to provide a flow control valve including an operating piston adapted to be held at a first open position by fluid pressure and biased toward a second closed position by a spring.

It is another object of the invention to provide a fluid flow control valve having a fluid actuated operating piston which is exposed at one end to fluid pressure for holding a valve member open and exposed at the other end to fluid pressure on the downstream side of the valve member to minimize the force required to move the valve member from a closed to an open position by fluid pressure applied to the piston.

It is a still further object of the invention to provide a fluid actuated flow control valve having a tube connected between an operating piston and a ball valve assembly with the tube being provided with an external annular seat for sealing engagement with a seat surface on a packing gland around the tube to provide a supplementary seal around the tube to prevent leakage in the event of destruction of the packing supported in the gland.

It is a still further object of the invention to provide a fluid flow control valve which may be moved to an open position by fluid pressure applied on the downstream side of the valve through the main central flow passage of the valve in the event of failure of the fluid control system of the valve.

It is a still further object of the invention to provide a fluid actuated flow control valve including means for both opening and closing the valve responsive to fluid pressure applied to a fluid actuated operating piston of the valve.

It is another object of the invention to provide a wellhead system including a Christmas tree cartridge which is removable independently of tubing string supported in a well from the casing head of the system.

It is another object of the invention to provide a method of equipping a well for fluid flow between its wellhead and a remotely located control station.

The invention is therefore directed principally toward a wellhead system wherein the tubing flow conductors in the well are positioned therein and supported in flow communication with a Christmas tree cartridge installed in the casing head to be completely enclosed therein, and having flow controlling valves disposed in the flow passage or passages of the Christmas tree cartridge for controlling flow from the well through the tubing string or strings connected with the Christmas tree cartride and thence to the flow lines from the wellhead. The valves are completely enclosed within the Christmas tree cartridge and are installable in and removable from the Christmas tree cartridge and are controllable from a remote point, whereby the device is particularly adapted for a submarine type installation and thus provides a valve assembly in a well which is protected from the action of the sea and other extraneous forces. The system is installed by lowering the tubing string into the well casing head in flow communication with the Christmas tree cartridge, sealing the same in place in the casing head with the valve means disposed in the Christmas tree cartridge in communication with the well flow conductors or tubing strings and in communication with operating fluid lines connected to the casing head in communication with the valves in the cartridge, and controlling the flow from the well through the cartridge by means of the valves from a remote point.

Additional objects and advantages of the invention will be readily apparent from the reading of the following description of a device constructed in accordance with the invention, and reference to the accompanying drawings thereof, wherein:

FIGURES l and l-A taken together constitute a longitudinal view partially in section and partially in elevation of a tubing master and casing annulus valve Christmas tree cartridge in accordance with the invention, illustrating in detail one of the fluid actuated flow control valves included in the cartridge;

FIGURE 2 is a reduced top view in elevation of the apparatus illustrated in FIGURE 1;

FIGURE 3 is an exploded perspective view of a ball valve assembly utilized in one of the flow control valves included in the apparatus of FIGURE 1;

FIGURE 4 is a view in section along the line 44 of FIGURE 1;

FIGURE 5 is a diagrammatic view in section and elevation of an intermediate stage in the installation of a wellhead in accordance with the invention showing a Christmas tree connected with tubing strings and related components being lowered to operating position in a well;

FIGURE 6 is a diagrammatic view partially in elevation and partially in section illustrating a completed wellhead in accordance with the invention connected with flexible flow lines;

FIGURE 7 is a fragmentary view in section showing an alternate form of tubing master and casing annulus flow control valves;

FIGURE 8 is a fragmentary view in section illustrating another alternate form of tubing master and casing annulus flow control valves;

FIGURE 9 is a fragmentary view in section and elevation showing an alternate wellhead arrangement in accordance with the invention; and

FIGURE 10 is a schematic illustration of the connection of the wellhead control and flow lines with a remote control station.

Referring to the drawings, a wellhead embodying the invention includes a casing head 21 positioned at the bottom 20a of a body of water 20b on the upper end of a string of casing 22 in a well bore 23. A tubing master and casing annulus valve or Christmas tree cartridge 24 having a case 24a is enclosed within the casing head to support and control fiuid flow from a tubing string 25 extending through an upper packer and a lower packer 31 and from a tubing string 32 extending through the upper packer. Well fluids from a lower formation 33 flow into the casing through several casing perforations 34 from where they flow to the Christmas tree through the tubing string 25. Well fluids from an upper formation 35 enter the casing through a plurality of perforations to flow to the Christmas tree through the tubing string 32. Fluids from the tubing strings flow from the wellhead to remotely located control and fluid separation and storage facilities, not shown, through the flexible flow lines 41 and 42, respectively.

The Christmas tree cartridge is a fully self-contained wellhead control unit or valve unit which is installable in and removable from the casing head through a conduit connected thereto, as discussed in detail hereinafter.

The Christmas tree cartridge includes a fluid actuated remotely controllable upper tubing master valve 43 and an identical lower tubing master valve 44 secured in a bore 24b of the Christmas tree case to control the fluid flow from the tubing string 32 into the flow line 42. Identical upper and lower master valves, not shown, are also included in a bore 240 of the Christmas tree case for control of the flow of well fluids from the tubing string 25 into the flow line 41. An upper casing annulus valve 45 and a lower casing annulus valve are secured in a bore 24d of the Christmas tree case for fluid communication with the casing annulus 51 through an annulus flow line 52. Control fluid for operating the tubing and the casing annulus valves is conducted to the wellhead through a plurality of control fluid flow lines 53 which extend to the control station with the flow lines 4 1 and 42.

' The tubing master valve 43 includes a tubular body mandrel 61 comprising an upper or head section 62, a central section 63, and a lower section 64. A valve assembly 65 is disposed within the body mandrel for movement between open and closed positions by a valve tube connected at one end to the valve assembly and at the other end to an annular piston 71 which is biased in one direction by a spring 72 and movable in the other direction by fluid pressure applied within the annular cylinder 72a.

The valve assembly comprises a ball valve 73 rotatably disposed between an upper seat surface 74 and a lower seat surface 75 on upper and lower valve seats and 81, respectively. The upper valve seat has a central bore 82 which communicates with a central bore 83 through the lower valve seat through a bore 84 extending through the ball valve when the ball valve is rotated to the position illustrated in FIGURE 1-A. The upper and lower valve seats are provided with fragmentary spherical sur faces 85 and around the upper and lower valve seat surfaces 74 and 75, respectively, spaced from the surface of the ball valve reducing the areas of the seat surfaces and thus minimizing the friction between the ball valve and the seat surfaces when the ball valve is rotating between open and closed positions.

The upper and lower valve seats 80 and 81 are confined on opposite sides of the ball valve within a cage 91 formed on the tube 70. The cage is provided with a plurality of downwardly extending flexible circumferentially spaced collet fingers 92 and a pair of longitudinal downwardly opening slots 93. Each of the collet fingers 92 has an inner boss 94 which is received around an annular retainer ring 95 below an external annular upper end flange on the retainer ring for releasably holding the cage on the retainer ring. A downwardly and outwardly facing external annular shoulder 101 defining the lower end surface of the flange 100 is engaged by an upwardly and inwardly facing shoulder surface 102 within each of the collet fingers. A wave spring 103 is supported within an upwardly opening recess 104 in the upper end face of the retainer ring 95 to yieldably support the lower valve seat 81 against the ball valve.

The upper valve seat 80 is held against upward movement by an internal annular downwardly facing annular shoulder surface 105 within the cage 91. The outer periphcry of the top or upper face of the upper valve seat is chamfered to provide an upwardly and inwardly convergent surface permitting an O-ring 111 to be confined within the cage between the surface 110, the upper end internal surface 105, and an internal tubular side surface 112 of the cage. In assembling the valve assembly 65 the ring seal 111, the upper valve seat, the ball valve, and the lower valve seat are consecutively placed within the cage followed by the wave spring and the retainer ring 95. The collet fingers 92 are sprung or spread outwardly to permit insertion of the various components of the valve assembly including the retainer ring. The bosses 94 of the collet fingers pass over the annular flange 100 on the retainer ring until the bosses spring inwardly with the shoulders 102 engaging the retainer ring shoulder 101 sufliciently tightly to place the wave spring 103 under compression biasing the lower valve seat against the ball valve to hold the ball valve between the upper and lower seats. The O-ring seal 111 is of sufiicient thickness that it is under compression between the upper valve seat and the cage surfaces to provide an initial fluid seal between the valve seat and the cage so that fluid will not bypass the ball valve between the upper valve seat and the cage surfaces. Fluid flow in either direction between the upper valve seat and the cage surfaces displaces the O-ring seal in a direction toward the lower pressure to more tightly wedge the seal between the cage and the upper valve seat to effectively prevent fluid flow in either direction between the valve seat and the cage.

A lower annular cap 113 is threaded on the retainer ring 95 and held against rotation by a set screw 114 threaded through a bore 115 in the cap into engagement at its inward end with the bottom end surface of the retalner ring. An upwardly extending annular flange 120 on the cap 113 fits around and overlaps the lower end sections 121 on the collet fingers 93- to lock the collet fingers inwardly around the retainer ring. A small amount of slack or tolerance is provided between the lower end sections of the collet fingers 92 and the cap 113 so that longitudinal downward loading on the valve assembly holding the cage downwardly when the ball valve is being held in open position does not so compress the assembly that the collet fingers are bent by contact with the cap 113. Downward force on the cage compresses the components of the assembly including the wave spring 103 until the lower face 122 of the lower valve seat engages the upper end face 123 of the retainer ring 95. When the wave spring is so compressed, the lower end surfaces 124 and 125 of the collet fingers do not engage the upwardly facing surfaces 130 and 131 on the cap 113 so as to impose a longitudinal load on the collet fingers. Thus, the spacing between the lower end surfaces 124 and 125 and the upper end surfaces 130 and 131, respectively, exceeds the space between the lower end face 122 on the lower valve seat 81 and the top face 123 of the retainer ring at the time when the shoulder 101 of the retainer ring is engaged with the surfaces 102 of the collet fingers. Therefore, a downward load on the valve cage forces the upper valve seat, the ball valve, and the lower valve seat downwardly to compress the wave spring so that the lower end face 122 of the lower valve seat and the upper face 123 of the retainer ring engage before the bottom surfaces 124 and 125 on the collet fingers contact the surfaces 130 and 131, respectively, of the lower cap 113, thus preventing longitudinal loading on the collet fingers.

A pair of pivot pins or lugs 132 project inwardly from the inner wall of the lower mandrel section 64 through the longitudinal slots 93 of the cage 91 into a pair of blind slots 133 in the ball valve 73. The pins extend co-linearly within the housing along a line offset from a diameter through the housing and the ball valve. In the open position of the valve wherein the valve bore 84 is aligned with the seat bores 82 and 83 the pins are positioned at the outward ends of the radially extending ball slots with the slots sloping upwardly and outwardly as illustrated. When the valve assembly is lifted the ball valve is raised relative to the pins. The pins slide in the slots 133 as they rotate the ball valve about its axis through substantially 90 degrees to misalign the bore through the ball valve and the bores through the seats so that the valve is closed against fluid flow therethrough. The upper and lower valve seats 80 and 81 are provided, respectively, with downwardly opening recesses 80a and upwardly opening recesses 81a, respectively, to provide longitudinal clearance for the pivot pins as the valve assembly moves relative to the pins between the open and closed positions of the valve. For example, in the open position of the valve, the assembly is at a lower end position so that the pivot pins extend through the recesses 80a in the upper valve seat. Similarly, when the valve assembly is at its upper end position, with the ball valve closed the pivot pins extend through the recesses 81a in the lower valve seat.

An annular packing bland 134 is secured around the tube 70 to support an annular packing 135 held within an internal annular upwardly opening recess 140 of the packing gland by a retainer ring 141 secured within the packing gland by a lock ring 142 inserted through a tangential slot, not shown, in the packing gland. The packing gland is secured in position by confinement of 1ts external annular flange 143 between the lower and upper outwardly divergent end surfaces 144 and 145 of the mandrel sections 63 and 64, respectively. The flange 143 has upper and lower outwardly divergent faces 146 and 147 which are formed at angles to mate with the upper and lower faces 144 and on the housing sections. A seal ring or gasket 150 is confined between each face of the flange 143 and the end surfaces of the housing sections. The seal rings preferably are of a metal such as copper which will form a fluid seal under compression.

The cage 91 is provided with an upwardly and inwardly convergent upper end seat surface 151 which engages a downwardly facing outwardly divergent lower end seat surface 152 on the packing gland 134 so that a metal to metal fluid tight seal is established between the upper end of the valve cage and the lower end of the picking gland when the valve is closed to prevent leakage around the cage through the gland in the event the packing 135 fails.

The annular piston 71 is fitted over the upper end of the tube 70 with the tube extending into an internal downwardly opening annular recess 153 in the piston. The piston is secured on the valve tube by a lock ring 154 which is inserted through a tangential slot, not shown, extending into the piston intersecting corresponding internal and external annular slots 155 and 160, of the piston and valve tube, respectively. An O-ring seal 161 is disposed in an internal annular slot 162 of the piston to seal between the valve tube and the piston.

The spring 72 is confined between a lower end surf-ace 163 on the piston and an upper end surface 164 of the packing gland 135 on the downstream side of the ball valve 73. The spring is sufficiently compressed within an annular space 165 between the tube 70 and the mandrel section 63 to lift the valve assembly to rotate the ball valve to its closed position in the absence of a predetermined fluid pressure within the annular cylinder 72a above the piston.

A plurality of radial, circumferentially spaced ports through the tube 70 vent the annular chamber 165 into the bore 70a through the tube to permit the piston and tube to reciprocate relative to the packing gland 134 without dampening action due to compression and rarefaction of fluid in the annular space 165. The bore 70a through the tube is enlarged along an upper end section 171 to receive a tubular filter 172 which covers the ports 170 to prevent foreign material, such as sand from passing from within the tube into the annular chamber 163. Such foreign matter could rapidly fill the annular chamber to render the valve inoperative. The filter 172 is formed of a suitable porous material such as ceramic or a sintered metal.

An external annular packing 173 is supported within an external annular recess 174 of the piston 71 to seal between the inner wall of the mandrel section 63 and the piston while allowing the piston to reciprocate within the mandrel section. The mandrel section is slightly reduced in internal diameter along an upper end section 175 providing a seat surface for the packing 173. The packing 173 is held against downward movement on the piston by a shoulder defining the lower end of the recess 174 and is held against upward movement by a retainer ring 181 secured on the piston above the packing by a split lock ring 182 which is inserted into corresponding inner and outer recesses 183 and 184 of the piston and lock ring, respectively, through a tangentially extending slot, not shown through the retainer ring intersecting the recesses 163 and 164.

The piston 71 is reduced in diameter along an upper end neck section 165 which extends upwardly in sealed relationship through an internal annular packing carried by the head section 62. The packing 190 is received in an internal annular downwardly opening recess 191 of the head section and is held against downward movement rel-ative to the head section by a retainer ring 192 which is locked in the head section by a split lock ring 193 which is inserted into corresponding inner and outer recesses 194 and 195 of the head section and retainer ring, respectively, through a tangential slot, not shown, in the head section. The packing is held against upward movement in the head section by engagement with a shoulder 200 defining the upper end of the recess 191.

The head section 62 in reduced in diameter along a lower end section 20-1 which fits telescopically within the mandrel section 63. A downwardly facing outwardly divergent annular shoulder 202 around the head section engages a washer or gasket 203 supported on an inwardly tapered upper end surface 204 on the mandrel section 63.

An external annular recess 205 around the head section communicates with a plurality of radially extending circumferentially spaced blind bores 210 which connect with a plurality of longitudinally extending circumferentially spaced bores or flow passages 211 formed in the head section permitting fluid pressure to be applied from the recess 205 through the head section into the annular cylinder 72a. The head section is provided with a pair of external annular upper and lower recesses 212 and 213, respectively, each of which receives an annular packing 214 for sealing above and below the recess 205 with the inner wall of the Christmas tree case 24a defining the bore 24b. Each of the packings 214 includes an O-ring seal 215 and backup rings 220 and 221 above and below the O-ring to prevent extrusion of the O-ring. Fluid pressure is communicatable into the recess 205 through a flow passage 222 formed in the Christmas tree case to conduct pressure control fluid from the surface control station through the case and the head section into the annular cylinder 72a for actuating the valve assembly.

With the exception of minor differences in their head sections, the master valves 43 and 44 are identical and thus all components of the lower master valve 44 are identical to those of the upper master valve 43.

The tubing master valves 43 and 44 are confined in end-to-end or stacked relationship within the bore 24b through the Christmas tree case. The lower master valve 44 is held against downward movement in the bore by an internal annular flange 230 providing an upwardly facing annular stop shoulder 231. An annular retainer 232 has an external annular flange 233 with an upwardly and outwardly sloping upper annular surface 234 and a lower annular surface 235 which engages the shoulder 231 to limit the retainer against downward movement is the Christmas tree case 24a. The mandrel section 64 of the lower master valve telescopes over the retainer 232 with a lower end surface 240 on the mandrel section being supported on a gasket 241 between the mandrel section and the shoulder 234 of the annular retainer. The retainer 232 has a downwardly and inwardly convergent annular support surface 242 which is engaged by a mating downwardly and inwardly convergent lower end surface 243 on the cap 113 of the lower master valve to limit the downward movement of the valve assembly 65 of the lower master valve.

The head section 62a of the lower master valve 44 is identical to the head section 62 of the upper master valve with the exception of certain hereinafter described details in the configuration of the head section above the upper seal recess 212 adapting the head section 62a to support the upper master valve 43. The head section 62a is provided with an external upwardly and outwardly opening annular recess 244 the lower end of which is defined by a downwardly and inwardly convergent annular shoulder 245 supporting a gasket 250 which engages a downwardly and inwardly convergent lower end surface 251 on the lower mandrel section 64 holding the mandrel of the upper master valve against downward movement within the 'bore 2401. A downwardly and inwardly convergent upper end surface 252 on the head section 62a limits the downward movement of the valve assembly 65 of the upper master valve by engagement with the lower end surface 243 on the retainer cap 113.

The upper master valve 43 is held against upward movement within the bore 24a of the Christmas tree case by an annular retainer ring 253 threaded into an upper end section 254 of the bore 24a over a reduced upper end neck section 255 of the head section .62. A lower end surface 260 of the retainer ring 253 engages an upwardly facing annular shoulder 261 on the head section 62 at the base of its neck section to confine the upper and lower master valves between the retainer ring and the annular retainer 232 at the lower end of the Christmas tree case. When both the lower and the upper master valves have been assembled and inserted into the Christmas tree case between the lower annular retainer 232 and the upper retainer ring 253, the retainer ring is threaded tightly against the shoulder 261 on the head section 62 of the master valve 43 to force the mandrel sections of the upper and the lower master valves together sufficiently tightly to establish a sealed relationship between the end surfaces of the mandrel section, the packing glands, and the gaskets interposed between them, such as the gaskets 203, and 250, so that the tubular mandrels of each of the master valves will not permit leakage of fluid from them. For example, under conditions both when the valves are open and when they are closed the lower mandrel section 64 of each valve is subjected to the upstream pressure within the well bore below the Christmas tree cartridge. The annular chamber and thus the gasket 150 is exposed to the pressure on the downstream side of the ball valve through the ports in the tube 70. The gaskets 264 prevent leakage from the cylinders 72a between the end sections 62 and 62a of the upper and lower master valves, respectively, and their respective upper mandrel sections 63. Therefore, the Christmas tree case serves a dual function of housing a plurality of tubing and easing valves and providing a connecting member between the lower annular retainers 232 and the upper retainer rings 253 since the valves do not each individually have casings which hold together and fully encloses all of their components.

The lower tubing master valve 44 is provided with control fluid under pressure through a flow passage 270 which extends through the Christmas tree case from its upper end to the annular recess 205 between the upper and lower packings 214 in the head section of the lower master valve.

Upper and lower master tubing valves, not shown, identical to the upper and lower valves 43 and 44 are secured in end-to-end relationship within the bore 60 of the Christmas tree case 24a in a manner identical to that of the valves 43 and 44. Control fluid under pressure is conducted to the upper and lower master valves in the bore 60 through the flow passages 27.1 and 272 each of which extends through the Christmas tree case from its upper and into one of the annular recesses 205 around the bore 60 of the upper and the lower master valves secured therein.

The upper and lower casing annulus valves 45 and 50 which are identical to and smaller than the valves 43 and 44, are supported within the bore 61 of the Christmas tree case to control fluid communication with the casing annulus through the wellhead. The casing annulus valves are controlled by fluid pressure conducted to the valves through the flow passage 280 extending through the Christmas tree case to the head section of the upper valve and through the flow passage 281 through the case to the head section of the lower valve.

The tubing strings 25 and 32 are suitably supported from and sealed with the lower end of the Christmas tree case to permit fluid communication between each ofthe tubing strings and its master control valves supported within the Christmas tree. The tubing strings are suspended from a suitable hanger flange 280 secured on the lower end of the Christmas tree case by a plurality of bolts 291. Each of the tubing strings is threadedly secured at its upper end into the hanger flange with suitable seals, not shown, bein provided between the flange and the lower end of. the Christmas tree case around the connection of each of the tubing strings into the bores 24b and 240 to prevent leakage of the fluids flowing from each of the tubing strings to its respective master valve. The flange 290 provided with a bore 292 communicating the casing valves with the annulus 51 within the casing annulus below the Christmas tree cartridge.

The Christmas tree case is supported against downward movement in the casing head 21 by engagement of a downwardly and inwardly converging annular surface 293 on the hanger flange 290 with a downwardly and inwardly convergent upwardly facing internal annular shoulder surface 294 at the lower end of the casing head 21. The Christmas tree case is held against upward movement by the engagement of a plurality of set screws or bolts 295 with an upwardly and inwardly convergent external annular surface 300. The bolts 295 may be either simple, large, set screw type bolts, as illustrated, which are secured by a diver when the wellhead is under water, or they may be any suitable forms of fluid actuated remotely controllable latching device for holding the Christmas tree case against upward movement in the casin head.

The upper end of the casing head 21 is closed with a suitable cap 301 which seals the casing head over the Christmas tree and connects the tubing, casing annulus, and control fluid lines into the Christmas tree cartridge. Ring seals 302 and 303 are carried by the head to seal with the outer surface of the Christmas tree case and the inner surface of the casing head, respectively. The tubing, casing annulus, and control fluid flow lines are suitably connected through the cap to communicate the proper flow lines with the appropriate bores of the Christmas tree case.

Each of the tubing, casing annulus, and control fluid flow lines is connected with a tubing or nipple section 304 secured through a control flange 305 of the cap 301. The tubing sections 304 each have a tapered or chamfered lower end surface for engaging an upper end seat surface 311 around a corresponding bore through the Christmas tree case. A seal pad 312 is confined between the flange 305 and the upper end of the Christmas tree case to seal around each of the tubing sections 304 secured through the flange. Typical suitable seal pads are illustrated in U.S. Patent No. 3,127,197 and at pages 1195-1205 of the Composite Catalogue of Oil Field Equipment and Services, supra.

The cap 301 is secured to the casing head 2.1 by a suitable remotely controllable latch or collet apparatus diagrammatically illustrated and referred to by the reference numeral 313. The collet apparatus includes collet fingers 313a which are received in an external annular locking recess 313b formed in the case 24a for holding the cap on the casing head. One suitable latch mechanism is illustrated and described in U.S. Patent No. 3,071,188 to G. M. Raulins. The Raulins latch is readily adapted to use with the case 2 4a by securing the flange 305 to the flange 1-8 of Raulins or by forming the flange 18 of Raulins to accommodate the tubing extensions 304 so that the tubing string, casing annulus and control fluid lines may be connected through the flange in sealed relationship into the top of the Christmas tree cartridge. Another remotely actuatable collet connector which may be adapted to secure the cap 301 on the casing head is illustrated at pages 1208 and 4252 of the Composite Catalogue of Oil Field Equipment and Services, 1964- 65 Edition, published by the World Oil, Houston, Tex. If the depth at which the wellhead 20 is to function is sufliciently shallow to permit diving operations the cap 301 may be secured on the casing head by providing the cap and easing head with suitable flanges and bolting the flanges together in a conventional manner.

During drilling and completion procedures the well 23 generally is equipped as illustrated in FIGURE 5. A suitabe. set of remotely actuatable blow out preventers 314 as illustrated at pages 4247 and 4258 of the Com- ,posite Catalogue of Oil Field Equipment and Services,

supra, is releasably connected on the upper end of the wellhead housing 21 by a suitable remotely controllable connector assembly, as illustrated in the U.S. Patent No. 3,071,188 to G. M. Raulins and at pages 1-208 and 4252 of the Composite Catalogue of Oil Field Equipment and Services, sup-r-a. A suitable conductor pipe 320 extends from the blowout preven-tors to above the surface of the water to provide a conduit through which drilling operations are carried out.

At the completion of the drilling of the well and the setting of the casing 22 within the well by conventional procedures, the tubing strings 25 and 32 along with the packers 30 and 31 are suspended from the Christmas tree cartridge and the tubing strings along with the Christmas tree are lowered into the well through the conductor pipe and blowout preventers until the Christmas tree cartridge is positioned within the wellhead housing 21 The Christmas tree cartridge is prepared for installation by assembly of the tubing master valves 43 and 44 and the casing annulus valves 45 and 50 in the bores 24b, 24c, and 24d of the Christmas tree case. The hanger flange 290 is connected on the upper ends of the tubing strings and secured on the lower end of the Christmas tree cartridge by the bolts 291. With the Christmas tree cartridge connected to the tubing strings and the tubing strings and Christmas tree cartridge suspended in the derrick structure, not shown, at the waters surface, a suitable handling tool 321 is releasably connected on the head end of the Christmas tree cartridge. The handling tool is supported from the running strings 322 and 323 which are suitably connected through the handling tool into fluid communication with the master valves in the bores 24b and 240 of the Christmas tree cartridge. A con-trol fluid line 324 is similarly connected to the handling tool to fluid communication with the bores 222 and 270272 for supplying control fluid from the surface to the tubing master valves so that the valves may be held in the open positioned as desired during the running in of the tubing strings and the Christmas tree cartridge and the setting of the packers 30 and 31. The connections through the handling tool of the handling strings and the control fluid lines are made in any suitable manner, such as illustrated in FIGURE 6 which shows the connections through the flange 305. Another control fluid line 325 extends to the handling tool to provide fluid pressure for connecting and disconnecting the tool and the case of the Christmas tree cartridge.

With the Christmas tree cartridge and tubing strings supported from the handling tool which is connected with the handling strings and the fluid control lines 324 and 325, the tubing strings and Christmas tree cartridge are lowered into the well through the conductor pipe until the Christmas tree cartridge is within the casing head housing 21 with the -lower end surface 293 resting on the shoulder 294 of the casing head to support the Christmas tree cartridge and the tubing strings. The bolts 295 are actuated either by diver or remote control if they are so operable, to engage the annular shoulder 300 holding the Christmas tree cartridge against upward movement in the casing head housing. During the lowering of the tubing strings from the surface to the position illustrated in FIGURE 6 the master valves are held in open position by control fluid pressure applied through the line 325 into the annular cylinders of the master valves Since the Christmas tree case generally is somewhat smaller in diameter than the flow passages through the conductor pipe the blowout preventers, and the casing head, the casing annulus valves may be left in the closed position :as the fluids, such as drilling fluid, extending upwardly into the conductor pipe may freely bypass the Christmas tree cartridge case as it is lowered into the casing head. However, when the Christmas tree cartridge case is seated and locked within the casing head the control fluid pressure through the line 3 30 is increased to open the casing annulus valves so that the procedures of circulating the drilling fluid out of the well casing and setting the packers may be carried out.

The drilling fluid within the well casing is circulated back to the surface and the packers 30 and 31 are set by conventional procedures. Oil or water may be used to circulate the drilling fluid out. If a separate control fluid line extends to the handling tool for controlling the master valves leading to the tubing string 32, such master valves are closed and water or oil is pumped at the surface into the running string 323. If the master valves connected with the tubing string 32 are not separately operable, a valve, not shown, at the surface connected with the handling string 322 leading to the tubing string 32 is closed to prevent fluid flow to the surface through the tubing string 32. The fluid .being pumped through the tubing string 25 from the surface flows from the lower end of the tubing string into the well bore and upwardly around the lower and upper packers both of which are not yet set. The displacing fluid then continues its flow through the annulus 51 within the well casing passing from the annulus upwardly through the casing annulus control valves 45 and 50 to flow back to the surface through the conductor pipe 320 around the running strings and control fluid pressure lines. After all of the drilling fluid has been circulated from the tubing string 25 and the casing annulus, the master valves leading to the tubing string 25 may be closed and those connected with the tubing string 32 opened to circulate in a similar manner the drilling fluid ifrom within the tubing string 32 back to the surface through the conductor pipe.

When the drilling fluid has been completely cleared from both the tubing strings 25 and 32 and the casing annulus, the upper and lower packers are expanded into engagement with the inner wall of the well casing 23 by suit-able conventional procedures. For example, the packers 30 and 31 may be fluid actuated packers in which a ball element is pumped into the packer to close a fluid flow passage through the packer. The fluid pressure is then raised in the tubing string and packer to effect expansion of the packer, and then subsequently the ball is pumped out of the packer through the lower end of the tubing string. Each of the packers is set to seal with the inner Wall of the well casing the tubing strings 25 and 32. Other suitable completion procedure, such as actual-1y producing the well from the upper and lower formations through the tubing strings, may be carried out to insure that well is in the desired condition for production prior to removal of the conductor pipe and the other equipment necessary for servicing the well.

After the well has been completed and will produce satisfactorily, the fluid pressure within the control fluid lines is reduced permitting the springs 72 to lift the annular pistons of the tubing master valves and easing annulus valves to closed positions. The control fluid pressure in the line 325 is adjusted to release the bandling tool 321 from the Christmas tree cartridge case after which the running strings, control fluid lines, and the running tool are lifted through the conductor pipe to the surface. The connector 315 is then actuated by fluid pressure applied through the line -316 to release it from the casing head 21 and the conductor pipe 320, the blowout preventers 3 14 and the connector are lifted to the surface.

The casing head cap 301 is then connected at the surface with the tubing flow lines 41 and 42, the casing annulus flow line 52, and the control fluid lines 53. The cap with the flow and control fluid lines connected thereto is lowered into position on the casing head 21 and secured as illustrated in FIGURE 6 so that the extensions 304 through the flange 305 of the casing head from the flow and control lines are connected in fluid tight relationship into the appropriate bores and flow passages of the Christmas tree cartridge case. If the cap of the casing head is securable on the casing head by conventional bolting, a diver is employed to maneuver the cap into the proper position and secure it to the housing. The positioning and sizes of the tubing master valve bores 24b and 240 and the casing annulus valve bore 24d through the Christmas tree cartridge case aids in properly orienting the cap on the casing head since the cap fits at only one position.

If the cap 301 includes a remotely actuatable locking assembly, the cap with its attached flow and control fluid lines may be guided into proper position on the well head housing by utilizing sub-sea guide line equipment of the type shown at pages 4247-5l of the Composite Catalogue of Oil Field Equipment and Services, supra. Where such procedure is followed the cap is lowered on the guide lines onto the casing head where it is remotely locked with the orientation of the cap assembly being predetermined by the positioning of the guide lines relative to the casing head and of the cap on the guide lines.

With the cap 301 locked as described above on the casing head, fluid flow from the producing zones 33 and 35 and fluid communication with the casing annulus 51 may be controlled as desired by the control fluid pressure which is applied to the tubing master valves and easing annulus valves of the Christmas tree cartridge through the flexible control fluid lines 53. In order to produce either or both of the formations 33 and 35 and to provide fluid communication into the annulus 51 the valves of the Christmas tree cartridge are opened by applications of control fluid pressure to the valves through the appropriate flexible control fluid lines extending from the remote control station to the Christmas tree cartridge through the cap 301. For example, fluid flow is permitted through the flow line41 by applying control fluid pressure into the flow passages 222 and 270 of the Christmas tree case to open the upper and lower valves 43 and 44 to allow fluid flow into the flow line 41.

Each of the :master valves function identically in the following manner. Control fluid under pressure is pumped into the annular recess 205. The fluid flows inwardly through the radial flow passages 210 and downwardly through the longitudinal passages 211 downwardly into the annular cylinder 72a where the control fluid pressure is applied to the piston 71 over an elfective annular area between the line of sealing engagement of the head section 185 with the packing 190 and the line of sealing engagement of the packing 173 with the inner wall of the control mandrel section 63. The control fluid pres sure applied downwardly against this effective area of the annular piston 71 is opposed by the spring 72 and by the pressure on the downstream side, that is above, the closed ball valve 73 as applied through the ports into the annular space 165 to an effective annular area of the piston 71 between the line of sealing engagement between the seal assembly 173 and the inner surface of the control mandrel section 63 and the line of sealing engagement between the packing 135 and the outer surface of the tube 70. The control fluid passage acting to open the valve also is opposed by the higher pressure below or on the upstream side of the ball valve 73 acting over an effective area of the ball valve assembly within the line of sealing engagement between the seat surfaces 151 and 152. The moment the seal between the seat surfaces 151 and 152 is broken the area over which the upstream high pressure is effective biasing the valve assembly upwardly is reduced to an effective area within the line of sealing engagement between the packing 135 and the outer surface of the tube 70. When the control fluid pressure within the annular cylinder 72a is increased to a level sufiicient to overcome the upward forces of the spring, the fluid pressure in the annulus 165, and the pressure below the closed ball valve, the piston 71 is forced in a downward direc- 13 tion moving the tube 70 and the ball valve assembly 65 downwardly until the lower end surface 243 on the annular cap 113 engages the annular surface 252 stopping the downward movement of the valve assembly with the ball valve having been rotated through substantially 90 degrees by hte pivot pins 132 as the ball moved relative to the pivot pins which are received in the recesses 133. With the ball valve in the position illustrated, the bore 84 through the valve is aligned with the upper and lower valve seat bores 82 and 83 to permit well fluids to flow upwardly through the bore 70a of the valve tube into the flow line 41 through which the Well fluids flow to the remote storage and treatment facilities, not shown.

In the beginning stages of opening the valve, as the piston 71 displaces the tube 70 and the valve assembly 65 downwardly and the ball valve is first cracked open or rotated slightly to a position where fluid may flow from below the valve through the bore of the valve, the differential between the higher shut-in pressure below the valve and the lower pressure above the valve begins to progressively reduce. This pressure differential across the valve is rapidly reduced so that the pressure within the tube 70 above the ball valve becomes substantially the same as the pressure below the ball valve. The increase in pressure in the tube 70 above the ball valve as the valve is opened is transmitted through the ports 170 into the annular space 165. Thus, as soon as the ball valve is rotated sufficiently to equalize the pressure across it the upward force applied by the higher pressure within the line of sealing engagement of the seat surfaces 151 and 152 diminishes and the pressure within the annular space 165 increases applying a larger upward force to the piston 71 over an effective area within the lines of sealing engagement of the packing 173 and the packing 135 with the body mandrel section 63 and the tube 70, respectively. This latter effective annular sealed area is preferably greater than the effective sealed area within the line of sealing engagement of the seat surfaces 151 and 152, and, therefore, when the ball valve is rotated sufficiently to open it to the extent that the higher pressure is applied into the annular space 165 a somewhat greater fluid pressure in the annular cylinder 72a is required to continue the downward movement of the piston 71 for rotating the ball valve to the full open position.

With the ball valve fully open as illustrated in FIG- URE l-A, the pressure within the tube 70 applied through the ports 170 into the annular space 165 sets on the piston 71 to bias it in an upward direction. In addition, the spring 72 biases the piston 71 upwardly so that the force of the fluid pressure in the annular space 165 combines with the spring 72 to urge the ball valve toward the closed position. So long as fluid flow is desired through the valve, control fluid pressure is applied from the surface into the annular space 72a to hold the piston 71 at the lower position as shown against both the force of the Spring 72 and the pressure Within the annular space 165. The filter member 172 over the ports 170 prevents the movement of solid particles from within the tube 70 into the annular space 165. Unless the annular space is so protected solid matter may enter the annular space to interfere with proper functioning of the valve. So long as sufficient control fluid pressure is maintained within the annular cylinder 72a of each of the tubing master valves and the casing annulus valves, the valves are held in the open position.

Any decrease in pressure within the annular cylinder 72a of each of the tubing master and the casing annulus valves below the level required to overcome the force of the spring 72 and the fluid pressure in the annular space 165 permits the valve assembly 65 to be lifted by the piston 71 to rotate the ball valve to the closed position. Such a decrease in pressure may be effected intentionally from the surface by reducing the control fluid pressure being applied into the lines 53 or by sufficient damage to the control fluid lines, the cap 301, or any of the other components of the well flow system to cause a loss of control fluid pressure. As soon as the pressure within the cylinder 72a drops below the level necessary to overcome the spring 72 and the pressure within the annular space 165, the spring and the pressure within the annular space lifts the piston 71 along with the tube 70 and the valve assembly 65 is in an upward direction. The entire valve assembly, including the cage 91, the upper and lower valve seats and 81, the ball valve 73, the retainer ring 95, and the cap 113 is lifted upwardly causing the ball valve to move relative to the fixed pivot pins 132. The action of the pivot pins in the slots 133 as the ball valve moves upwardly relative to the pivot pins causes the ball valve to be rotated through substantially degrees to misalign the bore 84 through the ball valve from the bores 82 and 83 of the valve seats so that fluid flow cannot take place through the ball valve. As soon as the ball valve has been rotated sufficiently to prevent fluid flow through its bore, which will be somewhat less than 90 degrees, the shut-in pressure of the Well below the ball valve biases the valve into sealed engagement -with the seat surface 74 of the upper valve seat 80 preventing fluid flow through the bore 8-2 of the upper valve seat around the ball valve so that the valve assembly 65 is urged upwardly by the higher shut-in well pressure below the ball valve over an effective area within a line of sealing engagement between the packing and the outer surface of the tube 70. As soon as the valve assembly 65, the tube 70, and the piston 71 are lifted to the upper end position at which the ball valve is fully closed, the seat surfaces 151 and 152 are engaged in sealed relationship along a line which is slightly greater than the line of sealing engagement between the packing 155 and the outer surface of the tube 70 to increase slightly the force of the shut-in pressure acting on the valve assembly holding the valve in the closed position. The engagement of the seat surfaces 151 and 152 provides an added factor of safety so that the valve will not leak along the tube 70 through the gland 134 in the event of damage to the packing 135. The force of the spring 72 also continues to urge the piston upwardly exerting a lifting force on the tube 70 to hold the valve closed.

As soon as the rotation of the ball valve has closed off flow through its bore, the shut-in pressure of the well is confined below the valve and thus the pressure within the tube 70 and consequently the pressure within the annular space is reduced to a minimum which may be the hydrostatic pressure of the fluid within the tube 70 above the ball valve. Of course, if valves at the control station in the flow lines leading to the valves in the well head are closed at the time the wellhead valves are closed, then the fluids within the wellhead valves and the flow lines leading to them may be trapped at a pressure some- What higher than hydrostatic pressure.

So long as the pressure within the annular cylinders 72a remains below the level required to overcome the spring 72 and the fluid pressure in the annulus 165 tending to open the valves, the valves will remain in closed condition.

Each of the tubing master and casing annulus valves is opened preferably by increasing the pressure within the annular cylinder 72a from the remote control station through the control fluid lines 53. As soon as the pressure within the annular cylinder is raised to a level suflicient to overcome the spring 72 and the well shut-in pressure below the ball valve, the piston, the tube 70 and the valve assembly 65 are moved downwardly as previously described to rotate the ball valve to the open position.

If, for some reason, such as the control fluid lines being damaged or destroyed, the pressure within the annular cylinder 72a of each of the valves cannot be raised to open the valves, each of the valves may be moved to an open position by fluid pressure applied through the flow lines leading to the valves, such for example as the flow lines 41 and 42 leading to the tubing master valves and 52 extending to the casing annulus 51. The fluid is pumped into the flow line leading to the particular valves which require opening. For example, if the valves 43 and 44 are to be opened by this method fluid is pumped into the flow line 42 so that fluid pressure is applied through the tube 70 above the ball valve forcing the ball valve downwardly. The increase in fluid pressure in the tube 70 above the ball valve is transmitted into the annular space 165 through the ports 170 in the tube. Since the packing gland 134 forms a part of the body mandrel of the valve and cannot be displaced downwardly, the pressure within the annular space 165 pushes the piston 71 in an upward direction while the pressure within the tube 70 above the ball valve forces the ball valve assembly along with the tube 70 in a downward direction. The forces acting downwardly on the tube 70 and upwardly on the piston 71 shear the lock ring 154 when the fluid pressure forcing the tube and piston in opposite directions is raised to a sufficient level. The shearing of the lock ring 154 releases the tube 70 from the piston so that the fluid pressure being applied through the tube 70 to the ball valve forces the ball valve and the other components of the valve assembly 65 along with the tube 70 downwardly to rotate the ball valve to the open position. As soon as the lock ring 154 is severed disconnecting the annular piston from the tube 70 the biasing force of the spring 72 and the fluid pressure within the annular space 165 are no longer effective to lift the tube in an upward direction. It will be recognized that when the ball valve is forced in the downward direction a sealing relationship will no longer exist with the seat surface 74 and the ball valve will be forced downwardly against the seat surface 75 on the lower valve seat. Leakage may occur around the lower valve seat between the collet fingers so that the fluid being forced against the upper side of the ball valve may flow to some extent between the ball valve and the upper valve seat surface 74 with the fluid passing downwardly around the ball valve and outwardly bet-ween the collet fingers within the lower body mandrel section 64. The extent to which the ball valve may be displaced downwardly is not so great, however, but that the ball valve may be moved to an open position by rapid pumping. It will be recognized that the destruction of the connection between the tube 70 and the piston 71 prevents further proper functioning of the valve Since the piston 71 cannot lift the valve tube either by the spring 72 or by the pressure within the annular space 165 to move the ball valve back to the closed position. Thus, pumping any of the valves to the open position by applying pressure directly to the ball valve is resorted to only under emergency conditions where this is the only way that the valve can be moved to the open position.

Two valves are provided in each of the bores 24b, 24c and 24d of the Christmas tree cartridge to provide a safety factor whereby the Christmas tree cartridge is not rendered inoperative due to the failure of one of the valves. Generally, the two valves in each bore are operated simultaneously though, if desired, they may be opened or closed individually. When both of the valves in a particular bore are closed, fluid will be trapped between the ball valve of the upper valve and the ball valve of the lower valve. Should it be desired, therefore, to open the upper valve first, displacement of some of the fluid trapped between the ball valves is necessary to permit the upper ball valve to move downwardly. Such displacement of the trapped fluid is permitted by the construction of the valve assemblies 65. As the upper valve assembly is displaced downwardly the fluid trapped between the balls forces the lower ball valve in a downward direction away from its upper seat surface 74 by compressing the valve spring 103 so that the trapped fluid between the ball valves may leak downwardly around the lower ball valve within its cage to a sufficient extent to permit the upper ball valve to be moved to the open position.

It will now be seen that a new and novel wellhead adapted for installation and operation at remote locations has been described and illustrated.

It will be further seen that the wellhead includes a Christmas tree in the form of a cartridge which is insertable into and removable from a casing head through a conductor pipe leading to the casing head.

It will also be seen that the Christmas tree cartridge includes a plurality of flow control valves actuatable responsive to fluid pressure applied to the valves from a remotely located control station.

It will also be seen that the Christmas tree cartridge includes at least one fluid actuated master valve for each tubing string connectable into the cartridge and at least one fluid actuated valve for controlling fluid communication into the casing annulus between the casing on which the Christmas tree is secured and any tubing strings supported from the Christmas tree.

It will also be seen that the Christmas tree cartridge case has no protruding or outwardly extending members or components thereby permitting the Christmas tree cartridge to be installed in and removed from a casing head through such equipment as blow out preventers.

It will also be seen that the wellhead including the Christmas tree cartridge is completely closed and sealed and thus may function within an environment such as sea water.

It will also be seen that the Christmas tree cartridge has a substantially tubular like body or case enclosing the flow control valves thereby minimizing the probability of exposing the functioning elements of the Christmas tree cartridge to water during installation and operation of the wellhead where the head is located at the bottom of a body of water.

It will be further seen that the Christmas tree cartridge includes fail-safe type fluid operated tubing and casing annulus valves.

It will also be seen that each flow control valve included in the Christmas tree cartridge includes an operating piston adapted to be held at a first open position by fluid pressure and biased toward a second closed position by a spring and fluid pressure.

It will be further seen that each of the flow control valves of the Christmas tree cartridge has a fluid actuated operating piston exposed at one end to fluid pressure for holding the valve open and at the other end to fluid pressure on the downstream side of a ball valve to minimize the force required to move the valve from a closed to an open position by fluid pressure applied to the piston.

It will be further seen that each of the fluid actuated flow control valves has a tube connected between an operating piston and a ball valve assembly with the tube being provided with an external annular metal seat for sealing with a metal seat surface on a packing gland around hte tube to provide a metal to metal seal around the tube to prevent leakage in the event of destruction of the packing carried by the packing gland.

It will be also seen that each of the flow control valves of the Christmas tree cartridge may be pumped to an open position by fluid pressure applied on the downstream side of the valve through its main central flow passage against its ball valve.

It will be additionally seen that each of the valves in the Christmas tree cartridge is operable by a fluid actuated annular piston operating during the initial phases of the opening of the valve against a minimum fluid pressure on the downstream side of a closed ball valve.

It will be further seen that a method has been described and illustrated for equipping a well with a wellhead adapted to permit flow control from a remote location as for example where an underwater wellhead is controlled from a station located at a shore position.

An alternative embodiment of the tubing master and e ing annulus valv s is. i lustrated in; FIGURE. 7,, which shows a modified form of the connection between the annular piston and the valve tube so that the valve may be pumped to an open position by fluid introduced into its central flow passage without damaging and thus rendering the valve inoperative. The same reference numerals as used in FIGURE 1 are used in FIGURE 7 to denote identical or substantially identical components of the valve. The annular piston 71a fits in slidable telescopic relationshi over the upper end section 70b of the valve tube 700. Relative movement of the piston 71a and the tube 700 toward each other is limited by an annular stop ring 350 which is secured on the tube 70c by a lock ring 351 which is inserted into corresponding external and internal annular recesses in the tube and stop ring, respectively, through a tangential slot, not shown, formed in the stop ring. While the stop ring 350 limits the movement of the piston and the tube toward each other, the piston and tube are free to move away from each other during the process of pumping the ball valve to an open position by fluid through the central bore 70a of the valve tube. The upper end section 70b of the tube extends into the enlarged bore 71b of the piston far enough that when the piston and tube are moved apart the maximum distance permitted a portion of the upper end section of the tube will remain within the piston so thatthe piston and tube do not become misaligned from each other when pumped apart. All features of the valve of FIGURE 7 are identical to the valve of FIGURE 1 other than the altered forms of the valve tube and the annular piston discussed above.

During normal operation, the valve illustrated in FIG- URE 7 functions substantially in the same way as the valve of FIGURES 1 and l-A. Control fluid pressure applied into the annular cylinder 72a is employed to open the valve and hold it in the open position. The control fluid pressure is applied into the annular cylinder 72a displacing the piston 71a in a downward direction so that the lower end 710 of the piston engages the upper end face 350a of the hold ring forcing the hold ring and the valve tube 700 in a downward direction to rotate the ball valve 73 to the open position in a manner identical to that previously described. When the pressure within the annular cylinder 72a is reduced to a value at which the downward force on the piston 71a is less than the upward force of the piston from both the spring 72 and the pressure within the annular space 165 below the piston, the piston and valve tube are moved upwardly rotating the ball valve to the closed position. Since the piston 71a fits in sliding relationship over the valve tube and is not directly connected therewith, any upward displacement of the piston does not actually lift the valve tube as in the embodiment of FIGURE 1 and thus the closing of the valve is eflected only by the lifting force of the spring 72 against the stop ring. It will therefore be obvious that the spring 72 in the embodiment of FIGURE 7 must be sufficiently strong to move the valve between the open and closed positions without the lifting force of the pressure within the annular space 165. Once, however, the valve is closed the shut-in well pressure below the ball valve exerts an upward force on the ball valve "in the manner previously described to hold the ball valve in the closed position so long as the pressure within the annular cylinder 72a remains at a sufficiently low level.

If a control fluid line failure or other malfunction of the control apparatus connected with the valve of FIG- URE 7 prevents the valves being opened by the normal procedure of raising the pressure in the annular cylinder 72a, the valve may be opened without damaging it by pumping fluid into the valve tube above the ball valve. Fluid is pumped from the control station through the particular flow line, such as one of the flow lines 41 and 42, connected with the valve to be pumped open. The fluid pressure applied above the ball valve of the valve forces the tube 70c downwardly while the pressure is transmitted through the ports 170 into the annular space below the piston 71a. While the tube 70a is being forced downwardly the piston 71a is forced in an upward direction by the pressure in the annular space 165. The slidable telescopic relationship between the piston and tube permits the piston to freely move upwardly on the upper end section of the tube until the upper end 71d of the piston engages the lower end 62a of the head section 62 limiting further upward movement of the piston. The downward movement of the tube 70a rotates the ball valve to an open position allowing the fluid being pumped into the valve tube 700 to pass through the ball valve downwardly into the well. Since the only force opening and holding the ball valve in the open position is the pressure differential developed across the valve in the fluid passing through the valve, the valve will not move to a fully open position but rather will fluctuate between various degrees of an open condition depending upon the rate at which the fluid is being pumped downwardly through the valve. When the pressure is reduced in the fluid being pumped into the well to a level below that required to overcome the force of the spring 72 the spring will lift the valve assembly rotating the ball valve back to a closed position. The opening of the valve by pumping downwardly through it is generally used as only an emergency procedure such as when it is necessary to stop the well from flowing by pumping in a high density liquid which will exert a hydrostatic pressure in excess of shut-in pressure of the well formation.

The embodiment of FIGURE 7 is not used to pump the valve to an open position for the purpose of producing the well. Since the only force holding the valve in the open position during the pump-down procedure is a pressure drop across the ball valve and since the spring 72 is constantly biasing the valve in the upward direction, the valve remains open to allow upward flow only when so held by the control fluid pressure in the cylinder 72a.

It will now be seen that there has been described and illustrated a form of fluid control valve which may be pumped to an open position by fluid pressure applied through a central flow passage in a direction opposite to the direction of the normal flow through the valve.

It will also be seen that the modified form of valve illustrated in FIGURE 7 includes a valve tube and an annular piston which are positioned in slidable telescopic relationship with each other.

It will be further seen that the annular piston fits in telescopic relationship over the valve tube and movement of the valve tube and annular piston toward each other is limited by a stop ring secured on the valve tube whereby movement of the piston toward the tube will effect movement of the tube while permitting the tube and piston to be moved apart from each other A still further modified form of flow control valve for use as a master tubing valve and a casing annulus valve is the Christmas tree cartridge of the invention is illustrated in FIGURE 8 wherein identical valve components are referred to by the same reference numerals as those used in the valve shown in FIGURE 1. The modified version of the valve shown in FIGURE 8 differs from the valve of FIGURE 1 only in that the annular space 165 of the valve of FIGURE 8 is not in communication with the central flow passage through the valve tube but rather is supplied with control fluid under pressure through suitable flow passages in the cartridge case and the packing gland 134a so that both the opening and the closing of the valve is controlled by the relationship of the pressures within the annular cylinder 72a and the annular space 165 independent of the pressure through the central flow passage of the valve tube. The valve tube 70d is a continuous solid member, not having the ports as is the valves of FIGURES 1 and 7, so that the central bore through the valve tube and the annular space 165 are not in fluid communication with each other. The packing gland 134a is engaged between the body mandrel sections 63 and 64 around the tube 70d supporting the packing 135a. The packing 135a is held against upward movement in the packing gland by the internal retainer ring 141 which is secured in position by the lock ring 142. An external annular recess 360 is formed in the packing gland 134a between upper and lower external packer rings 361 and 362 in recesses 361a and 362a of the packing gland to seal above and below the recess 360 with the wall defining the bore 24b through the cartridge case 24a. Fluid communication between the annular recess 360 and the annular space 365 is provided through the packing gland 134a by radial flow passages 363 and longitudinal flow passages 364. A flow passage 365 provided through the case 24a extending from the upper end thereof permits the control fluid to be transmitted through the case into the annular recess 360.

The valve of FIGURE 8 is opened in the same way as the valves of FIGURES 1 and 7 by pressure in the annular cylinder 72a to displace the tube 70d downwardly to rotate the ball valve to the open position. The forces opposing the opening of the valve and utilized in closing the valve are provided by the spring 72 and the fluid pressure within the annular space 165. During the opening of the valve the control fluid pressure in the space 165 as controlled through the passage 365 in the case 24a from the remote control station is maintained at a low enough level that the pressure within the cylinder 72a can overcome it and displace the piston 71 and the valve tube 70d downwardly to rotate the ball valve to an open position.

The valve of FIGURE 8 is shifted to the closed position by raising the control fluid pressure through the passage 365 to increase the pressure in the annulus 165 so that the spring 72 and the pressure in the annulus 165 will move the piston 71 and the valve tube upwardly to close the valve. The use of controlled pressure above and below the piston 71 permits positive control of the movement of the valve in both the upward and downward directions.

It will now be seen that a further modified form of fluid controlled flow control valve has been described and illustrated.

'It will be seen that the modified form .of flow control valve illustrated in FIGURE 8 provides means for applying fluid pressure from a source not related to the central flow passage through the valve into the annular space around the valve tube below the annular piston connected with the tube whereby the valve is movable to a closed position by pumping fluid from the surface control station into the annular space below the annular piston.

It will be further seen that the annular space around the valve tube below the annular piston does not communicate with the central flow passage through the valve.

It will be further seen that the valve illustrated in FIG- URE 8 is controllable between open and closed positions by adjustment of the fluid pressure in an annular cylinder above an annular piston connected with the valve tube and adjustment of the fluid pressure in an annular space around the valve tube below the annular piston independent of the fluid pressure within the central flow passage through the valve tube.

A modified form of wellhead and Christmas tree cartridge is illustrated in FIGURE 9 which shows a well system in which the tubing strings are hung in the well bore independent of the Christmas tree cartridge thereby permitting installation and removal of the Christmas tree cartridge independently of the tubing strings. Referring to FIGURE 9, the tubing strings 25 and 32 are suspended in the well bore 23 from a hanger flange assembly 370 which is supported in a casing head 371 secured to the upper end of the casing string 32. The Christmas tree cartridge 24 is removably secured in the casing head coupled with the hanger flange assembly.

The hanger flange 370 comprises a tubular body section 372 having longitudinally extending parallel spaced apart bores 373 and 374 providing flow passages for fluid communication from the Christmas tree cartridge into the tubing strings 25 and 32, respectively. Another bore 375 through the body provides a flow passage for fluid communication from the Christmas tree cartridge into the casing annulus 51. A lower cap 376 is secured in any suitable manner on the lower end of the body 372 and provided with the internally threaded bores 380, 381 for threadedly connecting and providing fluid communication into the tubing strings 25 and 32, respectively. A bore 375a through the cap provides fluid communication into the annulus 51 from the bore 375. The bores 380 and 381 are positioned to register with the bores 373 and 374, respectively, in the body section of the hanger flange assembly. The cap 376 has a downwardly and inwardly convergent lower end surface 382 to engage the downwardly and inwardly convergent upwardly facing surface 383 within the casing head for supporting the hanger flange assembly and limiting its downward movement in the casing head. A ring seal 384 carried by the cap 376 seals between the surfaces 382 and 383 on the cap and casing head, respectively. A plurality of set screws or bolts 385 extending through the casing head are received at their inward ends in an external annular locking recess 390 formed in the hanger flange body section to lock the hanger flange against movement in the casing head. Tubular extensions 391 each having an external ring seal 392 are secured to and extend downwardly from the bores 24b, 24c and 24d of the Christmas tree cartridge case to fit into and communicate with the flow passages 375a and 393 through the hanger flange assembly 370. The O-rings 392 seal around the tubular extensions 391 with the surfaces definings the bores through the hanger flange body section. Each of the tubular extensions has a lower end downwardly and inwardly convergent section 391a to correspond with the upwardly and outwardly divergent or flared upper end sections 393 of the bores through the hanger flange body to facilitate guiding the Christmas tree cartridge into position on top of the hanger flange assembly. A seal pad 394 of a suitable rubber or similar packing material is positioned between the top end surface of the hanger flange body section 372 and the lower end surface of the Christmas tree cartridge case to seal around the flow passage connections between the cartridge case and the flange body section. Set screws or bolts 395 are threadedly engaged through the casing head contacting the upwardly and inwardly convergent surface 300 on the Christmas tree cartridge case to hold the cartridge case against upward movement within the casing head. The hanger flange body section is provided with an upper external annular locking recess 396 for receiving a suitable handling tool, not shown, for use in installing and removing the hanger flange. The upper portions of the casing head 371 along with the apparatus for connecting the Christmas tree cartridge with the various flexible flow and control fluid lines are all identical to those previously illustrated and described in the wellhead system .of FIGURES 1 and l-A.

The wellhead 371 functions in a manner identical to the wellhead 20 while permitting a variation in the procedures followed in the installation and removal of the wellhead components. The tubing strings 25 and 32 are installed in the well by connecting them with the hanger flange assembly 370 which is lowered on a suitable handling tool, such as the previously described tool 321, to the position illustrated in the casing head and locked in position by the lock bolts 385 which are rotated until their inward ends are received in the locking recess 390 around the body portion of the hanger flange body section. The Christmas tree cartridge is then lowered is the previously described manner through the conductor pipe and the blowout preventers into the casing head until the lower end of the cartridge is resting on the upper end of the hanger flange assembly 370 with the tubing extensions 391 being received in the bores of the hanger flange body. The tubing extensions 391 on the Christmas tree cartridge case facilitate orientation of the cartridge relative to the hanger assembly since the positioning of the tubular extensions is generally triangular in accordance with the positioning of the bores through the cartridge case and the tubular extension connected with the bore 24d is smaller than the other tubular extensions of the cartridge case. The case can, therefore, be coupled into the hanger assembly at only one position. The cartridge case is manually rotated by a diver until it slides downwardly into the proper position .or it is guided into position by guide lines, as previously discussed.

In utilizing the wellhead system illustrated in FIGURE 9, the Christmas tree cartridge is installed in the casing head as above described and the well is then brought in and tested by suitable conventional procedures after which the master tubing and easing annulus valves are closed, the running tools are removed along with the conductor pipe, and the cap 301 and the flexible flow and control fluid lines are installed by following the previously described procedures.

The principal particular advantage of the Wellhead system of FIGURE 9 resides in the removability of the Christmas tree cartridge without disturbing the tubing strings 25 and 32. Suitable conventional procedures are followed to plug the tubing strings 25 and 32 and the flow passage 375 leading through the hanger flange assembly into the casing annulus 51. The lock nuts 395 are then retracted to release the Christmas cartridge so that it may be lifted upwardly from the casing head. The flexible lines along with the cap assembly 301 are disengaged from the casting head and the cartridge case following which the cartridge case is lifted with a handling tool, such as the tool 321, by conventional means from the casing head. The valves in the Christmas tree cartridge are serviced or replaced as desired and the Christmas tree cartridge is re-installed, if desired, in accordance with the original installation procedure.

If conditions are such that the well is not to be further produced, the casing head may be capped and sealed with a suitable blind flange, not shown, connected on the upper end of the casing head in the same manner that the cap assembly 301 is secured on the casing head.

It will now be seen that the modified form of wellhead arrangement illustrated in FIGURE 9 provides a wellhead adapted for remote use, such as at the water covered locations, wherein tubing strings are supported from a hanger assembly within a wellhead while a Christmas tree cartridge including master tubing string valves and casing annulus valves is installable in and removable from the casing head independent of the tubing strings.

It will be seen that the tubing hanger assembly is supported in and locked against upward movement within the casing head while the Christmas tree cartridge is independently lockable in the casing head above and in coupled relationship on the hanger assembly, the Christmas tree cartridge case having tubular extensions projecting into flow passages extending through the body of the tubing hanger assembly to provide fluid communication from the bores of the Christmas tree cartridge case into the hanger assembly.

It will be obvious that the lock bolts 385 and 395 in the wellhead illustrated in FIGURE 9 may be replaced by suitable remotely actuatable locking means to adapt the wellhead to use in water depths below the levels at which divers can function.

The foregoing description of the invention is explanatory only, and changes in the details of the construction illustrated may be made by those skilled in the art, within the scope of the appended claims, without departing from the spirit of the invention.

What is claimed and desired to be secured by Letters Patent is:

1. A method of equipping a well for fluid flow, said well having a casing head supported on a casing string and a conduit releasably connected to said casing head, said method comprising: lowering at least one tubing string having a packer supported thereon into the well through the conduit, said casing head, and said casing string to a predetermined depth within the well; supporting said tubing string in said casing head in flow communication with a Christmas tree cartridge having at least one flow passage therein, with the tubing string communicating with said flow passage of said cartridge; controlling flow through said flow passage of said cartridge by valve means disposed in said flow passage of said Christmas tree cartridge to control flow from the well through said tubing string and controlling actuation of said valve means from a remote point; withdrawing the means employed for installing the tubing string and packer in said well and said Christmas tree cartridge in said casing head; sealing said casing head over said Christmas tree cartridge; and connecting fluid flow and control fluid lines with said Christmas tree cartridge flow passage and said valve means of said Christmas tree cartridge for actuation of said valve means from a remote point.

2. The method of claim 1 wherein said tubing string is lowered into said well on a hanger flange, said hanger flange is releasably locked in said wellhead to support said tubing string from said wellhead, and said Christmas tree cartridge is lowered into said casing head and releasably locked therein in interconnected fluid communication with said tubing hanger whereby fluid flow between said remote control station and said tubing string and the casing annulus around said tubing string is controllable by said valve means in said Christmas tree cartridge.

3. The method of claim 2 including the steps of: maintaining sutficient fluid pressure within the valve means of said Christmas tree cartridge controlling fluid flow from said tubing string to hold said valve means open while lowering said cartridge into said casing head; circulating drilling fluid from within the tubing and casing of said well; and reducing the control fluid pressure within said valve means of said Christmas tree cartridge permitting said valve means to close prior to the step of sealing said casing head and connecting said fluid flow and control fluid lines with said Christmas tree cartridge.

4. The method of claim 1 wherein the steps of lowering said tubing string and said Christmas tree cartridge are effected simultaneously by supporting said tubing string at the upper end thereof in fluid tight sealed relationship from said Christmas tree cartridge and lowering said cartridge through said conduit into said casing head until said cartridge is supported against further downward movement within said casing head.

5. The method of claim 4 including the additional step of releasably locking said Christmas tree cartridge is said casing head after said cartridge is positioned within said casing head and held against downward movement therein.

6. The method of claim 5 wherein said conduit releasably connected on said casing head includes blowout preventer means.

References Cited UNITED STATES PATENTS 2,785,755 3/1957 En Dean 16672 3,064,735 11/1962 Bauer et al. 166-.6 3,318,377 5/1967 Otteman 166.6 3,322,192 5/1967 Woelfel et al 166.5 3,347,311 10/1967 Word l66.6 3,412,806 11/1968 Fredd et al. 166-72 DAVID H. BROWN, Primary Examiner U.S. Cl. X.R. 166-5, .6 

